Adjust wording of pre-flight check messages to be clearer (#457)

* Adjust wording of pre-flight check messages to be clearer
when presented as an AssertionError. Replaces #436.

* Update changelog

CHANGELOG.md

@@ -14,6 +14,7 @@ All notable changes to this project will be documented in this file.
 ### Changed
 - Load `DockerClientProviderStrategy` via Service Loader (#434, #435)
 - Make it possible to specify docker compose container in configuration (#422, #425)
+- Clarify wording of pre-flight check messages (#457, #436)
 
 
 ## [1.4.2] - 2017-07-25

core/src/main/java/org/testcontainers/DockerClientFactory.java

@@ -142,7 +142,7 @@ public boolean matches(Object o) {
 
             @Override
             public void describeTo(Description description) {
-                description.appendText("is newer than 1.6.0");
+                description.appendText("should be at least 1.6.0");
             }
         });
     }
@@ -162,7 +162,7 @@ private void checkDiskSpace(DockerClient dockerClient, String id) {
         DiskSpaceUsage df = parseAvailableDiskSpace(outputStream.toString());
 
         VisibleAssertions.assertTrue(
-                "Docker environment has more than 2GB free",
+                "Docker environment should have more than 2GB free disk space",
                 df.availableMB.map(it -> it >= 2048).orElse(true)
         );
     }
@@ -187,7 +187,7 @@ private void checkExposedPort(String hostIpAddress, DockerClient dockerClient, S
         } catch (IOException e) {
             response = e.getMessage();
         }
-        VisibleAssertions.assertEquals("Exposed port is accessible", "hello", response);
+        VisibleAssertions.assertEquals("A port exposed by a docker container should be accessible", "hello", response);
     }
 
     /**